Physical vs Chemical Changes Whats the Difference l

Physical vs. Chemical Changes

What’s the Difference? l l l Matter can change Examples: Freeze, cut, burn, etc. 2 types of changes 1. 2. Physical changes Chemical changes

Physical Changes l Matter changes form WITHOUT becoming something new – l You start and end with same thing (see below) Examples: cutting, freezing, melting, etc.

Molecules in Physical Changes

Chemical Changes l Matter changes, becomes NEW substance – l l Start and end with different things Usually irreversible (can’t change back) Examples: burning, rusting, milk going sour

Molecules in Chemical Changes l The atoms arrange to make a new substance

Chemical Change = Reaction l Reactants: starting solutions in a reaction l Products: the resulting solutions in a reaction

Signs of Change l Physical – – – Size Shape Texture l Chemical – – – Temperature Color Bubbles/fizzing Smoke Smell

Chemical Reaction Demo Na. HCO 3 + HOOCCH 3 l Baking Soda and Vinegar Na. OOCCH 3 + H 2 O + CO 2 Sodium Acetate, water, and carbon dioxide

Is it a chemical or physical change? l Sugar dissolving in tea • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l Logs burning • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l Breaking water up by separating it into hydrogen and oxygen • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l Cutting paper • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l Crushing an aspirin • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l Metal rusting • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l An egg rotting • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change? l An egg breaking • Chemical Change • Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Physical Change v. Chemical Change Make a Venn Diagram to compare the 2 types of changes